The invention relates to an independent suspension of a vehicle having a spring-link (control arm) structure which is constructed from a composite fiber material and which is constructed so as to be substantially U-shaped when viewed in the longitudinal direction of the vehicle. An upper member and lower member are secured at the end side to the vehicle body structure or a carrier which is connected thereto. At least one of these securings does not have any degree of rotational freedom about an axis which extends in the vehicle longitudinal direction, while a wheel hub is connected to the base of the U-shaped spring-link structure in order to secure a vehicle wheel. With regard to the prior art, in addition to DE 10 2008 043 330 A1, reference may be made to DE 102 16 244 A1 (having U.S. counterpart U.S. Pat. No. 6,616,159 B2).
Lightweight construction is becoming increasingly important in vehicle construction, in particular in passenger vehicles. In particular, a lightweight construction is particularly important in the field of vehicle chassis. In this context, wheel guiding elements may be constructed from composite fiber material and, consequently, in addition to a wheel-guiding function which has previously been performed by so-called wheel guiding links, also perform the function of a carrier spring which has previously been constructed in most cases as a helical spring and via which the vehicle body is proportionately supported on the respective wheel which is guided by the wheel guiding element. The two documents mentioned in the introduction disclose examples of such wheel guiding elements which are referred to in this instance as a spring-link (control arm) structure.
Based on DE 102 16 244 A1 mentioned above, it is an object of the present invention to provide a functionally advantageous independent suspension, which is distinguished by a small spatial requirement.
This and other objects are achieved in that at least one of the upper and lower members is substantially, that is to say, with the exception of low levels of elasticity, rigidly secured to the vehicle body or to the carrier mentioned. No additional wheel guiding link is provided which extends substantially in the longitudinal direction of the vehicle, for which reason, in order to achieve a desired increase of toe-in during braking, there is provided in at least one of the members a recess. The recess extends from the securing of the wheel hub to the base only over a part-region of the member in the longitudinal direction thereof.
According to the invention, unlike the prior art mentioned, no wheel-guiding longitudinal link or the like is provided, but instead the respective vehicle wheel is guided exclusively by the said spring-link structure which comprises a composite fiber material and which is U-shaped when viewed in the longitudinal direction of the vehicle. This, of course, minimizes the spatial requirement of an independent suspension according to the invention. To this end, at least one of the members is ultimately substantially rigidly secured to the vehicle body (where applicable, with the interposition of a carrier which will no longer be mentioned below for reasons of simplicity) so that this member of the spring-link structure can also perform the longitudinal guiding of the wheel. Ideally, a support base which is relatively wide or as wide as possible is intended to be provided between the member and the vehicle body, which will be discussed in greater detail below.
However, first explained herein is another inventively significant feature which is proposed in particular for use of such an independent suspension on the rear axle of a two-track vehicle, which axle is intended to be constructed as known in such a manner that the wheel during braking, that is to say, under the action of a braking force, moves increasingly in the direction of toe-in. Accordingly, in at least one of the members (and preferably in the upper member), there is provided a recess which extends from the base only over a part-region thereof in the longitudinal direction thereof, whereby starting from a “full cross-section” which is closed in the region of the connection of the member to the vehicle body, there are formed quasi two link portions which are separate from each other and which extend as far as the securing location of the wheel hub on the base of the U-shaped spring-link structure. When viewed in the opposite direction, consequently, starting from the securing location of the wheel hub to the spring-link structure according to the invention, on which securing location, for example, there may be retained a so-called wheel carrier on which the wheel hub is supported in a suitable manner, two mutually separate link portions of the spring structure lead in at least one of the members as far as a location at which these two link portions in a state adjacent to each other are combined to form a member portion which forms a full cross-section without any recess and which is then continued as far as the securing of this member to the vehicle body.
If the upper member of a spring-link structure according to the invention is now constructed in the manner described, there is (also) produced on this upper member under the action of a braking force which acts on the wheel and which is supported as a torque on the spring-link structure, a torsion moment. The torsion moment inwardly deforms in a downward direction the front link portion thereof when viewed in the travel direction in the region of the recess, and deforms outwardly in an upward direction the rear link portion thereof when viewed in the travel direction. This results in a desired increase of the toe-in of the wheel which is guided by the spring-link structure.
The effect which has just been described can be reinforced by the two members being substantially, that is to say, with the exception of low levels of elasticity, rigidly secured to the vehicle body or to the carrier mentioned and the recess being constructed in both members so as to be coherent over the base.
It has already been briefly mentioned that the securing of the “free” end(s) of the member(s) to the vehicle body is intended to form a support base which is relatively wide or as wide as possible in order to be able to achieve good longitudinal guiding of the wheel by the proposed spring-link structure. It is proposed as a preferred embodiment that the securing which is substantially, that is to say, with the exception of low levels of elasticity, rigid be constructed in the manner of a tongue and groove connection having a groove which extends substantially in the vehicle longitudinal direction in one of the elements which are intended to be connected to each other, and in which a connection structure of the tongue and groove connection, which structure is connected in an appropriate manner to the other element or which is provided thereon, engages in a positive-locking manner, with a resilient layer being interposed, and is retained in an appropriate manner. The resilient layer which is located therebetween is not only used for a desired acoustic decoupling between the wheel and vehicle body, but is also proportionately advantageous for a desired longitudinal resilience, that is to say, resilient action of the wheel suspension in the vehicle longitudinal direction (for example, with respect to occurrences of unevenness such as transverse joints or the like).
It is further optionally proposed that at least one of the members when viewed in the longitudinal direction of the vehicle, at the side thereof facing the vehicle front or at the front link portion, have a smaller thickness when measured in the direction of the vehicle vertical axis than at the side thereof facing the vehicle rear or at the rear link portion. The guided wheel thereby moves increasingly into toe-in under the action of lateral forces, as desired.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.
In all of the Figures, identical elements are indicated using the same reference numerals.